Line shorting contactor



May 28, 1946. F. L. KRADEL ETAL LINE SHORTING CONTACTOR Filed'May 7,1943 3 Sheets-Sheet l wuc/Wtou:

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sV H May 28, F L KRADEL EAL LINE SHORTING CONTACTOR Filed May 7, 1943 3Sheets-Sheet 2 May 28, 1946.

F. L. KRADEL ETAL LINE SHORTING CONTACTOR Filed May 7, 1943 3Sheets-Sheet 3 Patented May 28, 1946 LINE SHORTING CONTACTOR Fred L.Kradel and Rudolph Paulin, Greensburg,

Pa., assignors to Railway and Industrial Engineering Company,Greensburg, Pa., a corporation of Delaware Application May '7, 1943,Serial No. 486,()58

(Cl. ZUG-97) 13 Claims.

This invention relates to line shorting contactors that are employed on'electrical distribution systems .to suppress the flow of a faultcurrent by stablishing a metallic short circuit across the line at apoint between the current source and the fault.

Protective systems that include line shorting contactors are describedand claimed in the copending application of George A. Matthews, Ser. No.:333,875, filed May 7, 1940, Apparatus for protecting power lines",which became Patent No. 2,334,571 on November 16, 1943; and the presentinvention relates particularly to novel mechanical constructions forswitch devices that have the Operating characteristics of the lineshorting contactors described in that application.

An object of the present invention is to provide line shortingcontactors that include blocking mechanlsms of relatively simpleconstruction for preventing a reclosure of the shorting contactorimmediately after a fault-actuated closure and opening thereof. Anobject is to provide a line shortlng contactor that includes a counterfor registering the number of Operations thereof, and associated signalvanes for indicating the condition of the shorting ccntactor, i. e.,normal open condition, closed, or open but locked against reclosure.

These and other objects and the advantages of the invention will beapparent from the following specification when taken with theaccompanying drawings in which:

Fig. 1 is a vertical section through a line shorting contactor embodyingthe invention;

Fig. 2 is a fragmentary side elevation of the same as seen from theright of Fig. 1;

Fig. 3 is a schematic circuit diagram of the line .shorting contactor;

Fig. 4 is a fragmentary sectional View, on a larger scale, of the upperpart of the device as seen from the rear of Fig. 1;

Fig. 5 is a perspective view of the part of the mechanism for blocking areclosure of the line shorting contactor; and

Figs. 6, '7 and 8 are schematic views illustrating the control andindicating mechanism in, respectively, normal position, contactor closedposition, and contactor locked-out position.

The protective switch or line shorting contactor is a, fully automaticself-contained unit within a chamber comprising a hollow insul'ator nhaving an approximately cylindrical metal casting I I cemented to itsupper end to receive the domed cover [2 that termlnates in a flanged oilfiller opening to which the filler cap !3 is threaded.

The cap s has a flange or skirt that fiares away from the cylindricalthreaded section to cover vent openings M that extend through the cap,and the top portion of the cap is formed as a lifting ring. The lowerend of the insulator ti! is closed except for a central bore throughwhich a line shorting circuit connection extends, as will be more fullydescribed hereinafter. The outer surface of the insulator is preferablyof the usual petticoat type or is otherwise circumferentially grooved toreceive a supporting bracket !5 by which the shcrting contactor ismounted on a pole at any desired point in the circuit.

A source or line terminal !6 enters the casting or shell II through aninsulating bushing I?, and a load terminal s is integral with the shellH. The Operating winding of the contactor preferably comprises two coilsIS, !9' of the same or of different designs that may be co-nnected tothe terminals s, !8 in parallel or in series, the series connectionproviding a mld-point tap that adapts the contactor for use at a pointalong the line at which there may be a reversal of the direction ofcurrent flow under some Operating conditions. The series connection ofthe coils !9, 19' is illustrated in Figs. 1, 2 and 3. A connecting strap20 joins the line terminal [6 to the lower end of coil I 9, and the lead2! from the upper coil end extends downwardly along the I coil and isSecured to the strap 22 that is bolted to one end of a yoke 23.

A strap 24 connects the other end of the yoke 23 to the lower terminalof coil s', and the upper coil terminal 26 is bolted to the flexiblejumper 21 that extends to the metalllc supporting structure and therebyto the line terminal !8. Flexible jumpers 28 connect the opposite endsof` the yoke 23 to the shorting contact 29, Fig. 3, that is moved intoengagement with the cooperating contact 30 upon a predetermined currentflow through the coils te, IQ'.

The coils are connected in series in one conductor L of a tWo-Wiredistribution system by means of the terminals !6, !8, and the othercontact 3!! of the shorting contactor is connected to the otherconductor L,-' i. e., the distribution circut is short-circuited by aclosure of the contacts 28, 30 upon the occurrence of a fault thatresult in excessive current flow. The shorting contactor closes in fromto 2 cycles, on a cycles per second distribution system, and results ina heavy current flow through the metallic short-circuit that operatesthe circuit protective equipment, for example the circuit breakers of adistribution system such as illustrated in the copending Matthewapplication, and stops the flow of current at the fault point, therebyprotecting the line conductors against burnofi. The interrupticn ofcurrent flow at the circuit breaker deenergizes the coils 19 IS', andthe shorting contactor opens and is prevented from reclosing for apreselccted period during which the protective equipment operatesthrough a series of reclosures to a locked-out condition in the event ofa permanent fault. The mechanism for delaying a reclosure of theshorting contactor preferably includes both a mechanical lock-out thatwill be described later and a switch, comprising Contacts 3l, 32, forshunting the coils !9, 19.'

The coils !9, 19' each comprise a single or multiple layer solenoidwound from flat copper bar and having both terminals at one end of andat diametrically opposite sides of the coil. The coils are mountedwithin a laminated yoke 33 and reversely arranged to locate aliterminals at the level of a transverse plane at the center of the coilassembly. This terminal design and coil arrangement simplifies theConstruction of the circuit elements for connecting the coils in seriesor in parallel. Skeleton plates 34, 34' are riveted to the outer sidesof the magnetic yoke 33 and ar Secured by bolts 35 to an upper pair ofskeleton plates 36, 36' that have integral ears for securing theskeleton frame assembly to and grounding it upon the casting l I. TheOperating coil or coils !9, l9' are anchored in fixed position bypressure screws 31 that extend through lugs of the frame plates 34, 34'.

The lower central section 38 of the yoke rests upon a rubber cushioningmember 39 and serves as a stop for the armature 40, the cushioningmember 39 bein supported on a plate 4| that is Secured to the plates 34,34'. The armature 40 comprises laminations bolted to the switch rod orplunger 42 that extends above the armature to Carry a part of, and toactuate, the control mechanism. The movable contact 29 is secured to andinsulated from the plunger 42 by a bushing 43 of insulating material.The cooperating contact 30 comprises a cylindrical assembly of resilientstrips of a copper or bronze alloy carried by a bridge member 44 that isSuspended below the supporting plates 34, 34' by straps 45 of insulatingmaterial. The conducting yoke 23 is mounted on one of the insulatingstraps 45. The bridg 44 has a central bore for guiding the stem 46 thatcarries a conical contact 41 and is pressed by spring 46 towards aterminal assembly at the base of the insulator 10. Flexible jumpers 49connect the bridge 44 to the contact 41 to provide a low resistance pathfor current flow when the shorting contactor is closed. The fixedterminal assembly comprises a stud 50 having a conically recessed headto receive the contact 41, and a stem that extends through the insulatorl and has a lower end upon which the terminal member l is threaded.

When the coils l9, IS' are connected in parallel, the yoke 23 is notnecessary and the shorting contact 29 is mounted directly upon theplunger 42 that is grounded on the supporting structure and therebyelectrically connected to the terminal 18.

The mechanism for blocking a reclosure of the line shorting Contacts 29,30 is illustrated in Figs. 1 and 4, and different stages of oneOperating cycle are shown somewhat diagrammatically in Figs. 6-8. Thestern 52 of the movable contact 32 of the shunting switch extendsthrough and can rock on a double arm or bridge member 53 that ispivotally supported on a fixed shaft 54, and a fiexible jumper 55extends through a sleeve 56 of the mor/able contact assembly and itsends ar bolted. to the supportin frame, preferably by the same bolt 35that clamps the flexible jumper 21 to the frame plate 35', to provide alow resistance connection between the movable contact 32 and th lineterminal !3. The bridge member 53 is urged clockwise by a helical spring51 that has ends hearing on member 53, intermediate side sections coiledabout the shaft 54 and a central section engaging the Operating andcontrol arm 53; and the angular movement of the bridge member 53 islimited by the engagement of its crossbar 53' with the Operating arm 58,see Fig. 5.

The Operating and control arm 53 is pivoted on the shaft 54 andcomprises a U-shaped member 59, hardened steel end bar 60 that connectsthe side bars of member 59, and a U-shaped or double-armed leaf spring6! within the member 59 and riveted to the end thereof. The bridgemember or contact-carrying arm 53 and the Operating arm 50 are urgedcounterclockwise, i. e., towards open circut position, by the coilspring 62 that is connected between the arm 53 and the supporting plates36'. The ends of spring 65 flar inwardly and co-o erate with adownwardly directed spear-shaped member 63 on the plunger 42 to form aone-way coupling between the plunger arm 50 and the plunger 42. Thespear-shaped member 63 spreads the ends of springs U! When the plungermoves down in response to a predetermined current flow through the coils13, iS'. Upon interruption of current flow through coils 19, l9', theplunger 42 is lifted by the spring 64, and the control arm 59 i thenturned clockwise, to close the shunting contacts 3I, 32, by engagementof the upper radial surfaces of th member 63 with the ends of the leafsprings 6 l.

The mechanism for mechanically looking the shunting Contacts in closedposition includes the looking lever 65 and trigger 66 that are pivotallymounted on the plates 35, 36' by a shaft 61, the lever 65 and trigger 66being normally retained in approximate alinement by a spring 69. Thetail of the trigger 65 normally rests against the crossbar 65' of lever65, and it strikes a stop pin 10 to arrest the trigger in lookingposition when the lever 65 is forced down by the lug 1! that is fixed tothe plunger 42.

The lever 65 is coupled by a link 13 to the arm 14 of a time delaymechanism that impo'ses substantially no delay upon the clockwisemovement of lever 65 upon downward movement of plunger 42 to close theshorting contacts 29, 30, and that delays the return movement of thelever into unlocking position. The time delay mechanism may be of anydesired type and, as illustrated, the arm 14 is secured to a shaftcarrying a ratchet wheel 15 that is coupled by pawls 16 or overrunningclutch to a gear 11 of an escapement mechanism, not shown. Rotation ofarm 14 and shaft by link 13 coils a spring, not shown, that tends torotate the arm 14 clockwise to lift the link 13 and locking lever 65.Gear 11 `is loose on the shaft, but is driven through the pawl andratchet mechanism when the hait is rotated clockwise, thue delaying thelifting of the link 13 and locking lever 65.

The lever 65 is connected by link 18 to the operating arm of a Veedercounter 19 that is mounted within the casting ll at a window throughwhich the counter is normally exposed to View.

Signa vanes 8l, 82 are carried by levers 83, 84, respectively, formovement into line with the window opening when the shorting contacts29, 30 are closed and when the shorting contacts are open but lockedagainst closure. The vanes 81, 82 are of diiferent colors, for examplered and yellow respectively, to indicate the different condition ofadjustment of the shorting contactor. The signal vanes are normallymoved away from the window opening by the sprin 85 that joins the levers83, 84, and the vanes are moved into operative positions by a resilientconnection 86 from plunger 42 to lever 33, and by a link 81 from thebridge member 53 to the lever 84.

The method of operation of the shorting contactor will be apparent froma consideration of Figs. 6, '7 and 8 that illustrate the positions ofthe several elements of the control mechanism whenmespectively, (l) thecontactor is in normal inactive condition, (2) when the shortingcontacts 29, 30 are closed, and (3) when the shorting contacts 29, 33are open and locked against reclosure. A fault on the line L, L' resultsin excessive current fiow through the windings le, lil' and the plunger42 is moved downwardly by the armature 40 to close the shorting contacts29, 3& The control and indicating mechanisms are then in the positionsillustrated in Fg. 7. The control arm 58 has not changed position butthe spear member 63 on plunger .2 has forced aside the leaf springs aiand moved below the same. Lever 65 was forced down by the lug 'H onplunger 42, and set the time delay mechanism by pulling down the arm 74.The trigger 66 moved clockwise with lever 55 until its tail engaged thestop pin 10, and the counter la was actuated by the lever 65. The vane8! was moved downward into line 'with the window opening 80 by itsspring connection 85 to the plunger 42.

Upon interruption of current flow through the coils !9, IS', byoperation of the circuit breakers or otherwise depending upon the designof the protective equipment, the plunger 42 is lifted by the spring G ito open the shorting contacts 29, 30. The contro mechanism elements thenoccupy the positions illustrated in Fig. 8. The control arm 58 is turnedclockwise by the spear member 63, thereby closing the contacts 31, 32that Shunt the coils iii, iii' and block a reclosure of the shortingcontacts. The end bar 60 of the control arm forces the trigger 66 asideas the arm 53 is lifted, and then rests upon the end surface of thetrigger when the spear member 53 moves above the leaf springs Si and thearm 58 is turned counterclockwise by the spring 62. This partial returnmovement of the arm 58 bring the encls of the leaf springs 61 against orclosely adjacent the sloping surfaces of the spear member 63 andmechanically locks the plunger against downward movement. The signalvane 8! moved out of the window openingwhen the plunger 42 lifted butthe vane 82 was movedinto the window opening by thelink 87 when theshunting contacts closed. The lever 65 is rotated counterclockwise bythe link ?3 and the' time delay mechanism and, after a preselectedinterval, the crossbar 65' of the lever 65 engages the tail of thetrigger 66 and moves the trigger out of the path of the control arm 58.The control arm 58 is then moved counterclockwise by the spring 62, andthereby the shunting contacts 3l, 32 are opened and the mechanical lockagainst reclosure i removed. All parte then occupy their normalpositions as illustrated in Figs. 1, 3, 4 and 6.

The Operating coils 19, I 9' and restoring spring 12 are so related thatthe shorting contacts 29, 30 close substantially instantaneously, i. e.,in from %20 to of a second, upon the occurrence of a fault, thussuppressing the flow of fault current by placing a metallic shortcircuit upon the line. The short circuit current actuates a circuitinterrupter (fuse or circuit breaker) to remove the voltage from theline, and the shorting contacts are then opened by the restoring spring64 and are locked out for a predetermined period to permit the circuitinterrupter mechanism to operate through a series of reclosures to alockout in the event of a permanent fault. The great majority .of allfaults are of a transient nature, however,

and normal service is usually restored upon the first reclosure of thecircuit interrupter mechanisin.

There is considerable latitude in the design, Construction and relativearrangements of the several elements of the shorting contactors and ittherefore is to be understood that various changes may be made in thedisclosed constructions without departure from the spirit of ourinvention as set forth in the following claims.

We claim:

1. A line shorting contactor of the type including a normally openswitch having a, fixed and a movable contact for connection to oppositesides of a power distribution line, electrically actuated switch closingmeans including a plunger carrying the movable contact for closing saidswitch, and blocking means operative upon an opening of said contacts toprevent reclosure thereof for a predetermined interval, characterized bythe fact that said blocking means comprises a pivotally mounted arm, aone-way coupling for moving said arm into actuated position upon aswitchopening movement of said plunger, said coupling comprising amember on said plunger and spring means on said arm in the path of saidmember and deflectible therefrom by the member on a switch-closingmovement of said plunger, spring means tending to return said arm fromits actuated position, and means including a time-delay mechanism forcontrolling the return of said arm from its actuated position.

2. A line shorting contactor as recited in claim 1, wherein saidblocking means includes a normally open switch for rendering said switchclosing means inoperative, and means movable by said arm on displacementinto actuated position to close said second switch.

3. A line shorting contactor as recited in claim 1, wherein saidblocking means includes means on said plunger and cooperatng with saidarm for looking said plunger against switch-closing movement when saidarm is in actuated position.

4. A line shorting contactor as recited in claim 1, wherein said memberon said plunger and said spring means on said arm have cooperatingsurfaces locking said plunger against' switch-closing movement when saidarm is in actuated position.

5. A line shorting contactor as recited in claim 1, wherein saidblocking means includes a normally open switch for rendering said switchclosing means inoperative, and means movable by said arm on displacementinto actuated position to close said second switch; and said member onsaid plunger and said spring means on said arm have cooperating surfaceslooking said plunger against switch-closing movement when said arm is inactuated position.

6. In a line shorting contactor, a normally open switch having contactsfor connection to opposlte sides of a power distribution line,electrically actuated means including a plunger for closing said switch,and means mechanically looking said plunger against a switch-closingmovement upon a switch-opening movement thereof; said locking meansincludin a pivotally mounted control arm, a one-way coupling including amember on said plunger for moving said control arm to actuated positionupon a switch-opening movement of said plunger, a pivoted trigger memberengageable with said control arm when in actuated position to preventreturn thereof to normal nonactuated position, and time-delay means formoving said trigger member out of engagement with said control arm,thereby rendering said looking means inoperative.

'7. In a line shorting contactor, the invention as recited in claim 6,in combination with switch means operable by movement of said controlarm to actuated position to render said electrically actuated meansinoperative.

8` In a line shorting contacto' including normally open switch Contactsand means including a plunger for closing said switch Contacts;blocking' means to prevent reclosure of said. switch contacts upon anopening thereof, said blocking means comprising a pivotally mountedcontrol arm and means for moving the same into actuated position upon aswitch-opening movement of said plunger, a trigger, a. locking leve`operable by said plunger on a switch-closing movement thereof to movesaid trigger into the path of return movement of said control arm, andmeans including said locking lever and a time-delay mechanlsm for movingsaid trigger out of the path of return movement of said control arm.

9. In a line shorting contacto' including a pair of normally open switchContacts and means including a plunger for closing said switch contacts;blockin means for preventing a reolosure of the switch Contacts upon anopening thereof, said blocking means comprising a control arm, aresilient one-way coupling of said plunger to said control arm formoving the latter to actuated position upon a switch-opening movement ofthe plunger, and looking means for preventing return of said control armfrom actuated position, said looking means including a looking lever andmeans on said plunger for moving said looking lever into actuatedposition upon a switch-closing movement of said plunger.

10. In a line shorting contactor, the nvention as recited in claim 9wherein said control arm comprises a pivotally mounted member havingside bars at opposite sides of said plunger; and said resilient one-waycoupling includes a leaf spring, Secured within said mounted member andhaving inwardly flared ends, and a spear-shaped member on said plungerfor pressing aside and moving beyond the ends of said leaf spring memberupon a switch-closing movement of said plunger,

11. In a line shorting contactor, the invention as recited in claim 9,in combination with means operated by said control arm for renderingsaid contact-closing means inoperatve upon movement of said control arminto actuated position.

12. In a line shorting contactor, a pair of normally open switchcontacts electrcally actuated means i'or closing said switch contactsupon excessive current flow, means for separating said switch contactsupon a removal of voltage after a closure of said switch contacts, meansfor blocking reclosure of said switch Contacts for a predeterminedinterval after an opening thereof, a counter operated by said blockingmeans for registering the number of closures of said switch Contacts, asignal vane, and means operable by said electrically actuated means tomove said signal vane to prevent obse'vation of said countersimultaneously with a closure of said switch contacts.

13. In a line sho'ting contactor, the invention as recited in claim 12,in combination with a second signal vane, and means for displacing thesecond signal vane into position to block observation of said counter,said displacing means being operable by said blocking means uponactuation the'eof to block a reclosure of said switch contacts.

FREE L. KRADEL. RUDOLPH PAULIN.

